Carbon fibre reinforced plastics - MAI Recycling project completed

Projekt

Together with AUDI, BMW, Neenah Gessner, SGL Carbon, Siemens and Voith Composite, as well as the Fraunhofer Institute of Building Physics, bifa has worked on the MAI recycling project for more than three years.

The objective was further development of the recycling of carbon fibre reinforced plastics (CFRP) with a view to technical realisation. bifa‘s role within the project was that of project coordinator.

Apart from work on all aspects of pyrolysis, bifa‘s main tasks included extensive tests on the size reduction of CFRP and on the clean-up of exposed CFRP carbon fibres. The results were used to deduce concepts for adapted size reduction of the CFRP. In addition, the possibilities of removing contaminants from exposed carbon fibres can now be assessed realistically. A central project step was an industrial-scale CFRP recycling test with 3 t of real production waste: The test covered the complete process chain: from the preliminary size reduction and grading to exposing the carbon fibres from the plastic matrix by means of pyrolysis through to the processing of various semi-finished products.

Coordinating the whole process chain with the processing of the recycled fibres proved to be an important factor critical for success. Targeted control of the size reduction and grading to adjust the fibre length distribution and to reduce fibre losses in the recycling process are also critical for success. Based on practical testing of different methods of producing semi-finished goods from recovered carbon fibres, courses of actions to avoid faults and to improve processability were also deduced.

There is a need for development throughout the whole process chain, but the core processes for CFRP recycling are available. The most important task now is to develop recycling markets for products made of recycled carbon fibres.